1. Field of the Invention
This invention lies in the field of valves for the control of flow of fluids. More particularly, it concerns a plug valve in which a tapered plug is seated in a tapered cavity in a housing, so that seal can be provided between the plug and the wall of the cavity.
Still more particularly, it concerns a flow diverter valve having four radial openings in a transverse plane, at right angles to each other, communicating from the outside of the housing to the inner conical cavity, and the plug has two parallel channels cut into the conical surface so that in selected operating positions one channel connects to two adjacent openings and the second channel on the opposite side of the plug connects the two other openings. By rotating the plug 90.degree. the flow directions are changed.
2. Description of the Prior Art
In the prior art there are numerous descriptions of rotary valves with tapered plugs in correspondingly tapered seats or cavities, and with suitable sealing members to seal the openings through the conduits of the plug against the interior surface of the tapered cavity. However, in order to maintain this seal, constant pressure is applied to the plug by spring means, or otherwise, on the top surface of the plug, that is, the surface having the largest diameter of the plug.
With this strong pressure maintaining the plug tightly in contact with the interior wall of the cavity, there is often great friction, which makes it difficult to rotate the plug. Furthermore, rotating the plug under this high degree of friction damages the sealing members, which must be replaced frequently.
This invention is adapted to minimize the wear and tear on the sealing members, and also to provide a relatively friction-free rotation of the plug, except in the narrow zone of rotation where the plug is to be positioned with respect to the openings of the valve.